Ignition lag control



Feb. 7, 1939- c. c. MOORE. JR 2,146,265

IGNITION LAG CONTROL Filed June 28/1935 Ozone I zlCfiezzerafo ExhaustAz'r In Zaire Uzazzz'ze 2* IN V EN TOR. Charles C. Moore Jr BY M hATTORNEY.

Patented Feb. 1939 IGNITION LAG CONTROL Charles Chilton Moore, Jr.,Palos Verdes Estates,

Calif., assignor to Union Oil Company of California, Los Angeles,Calif., a corporation of California Application June 28, 1935, SerialNo. 28,893

9 Claims.

This invention relates to control of the combustion rates of liquidfuels in internal combustion engines and particularly to ignition lagcontrol in solid injection, compression ignition, in-

5 ternal combustion engines such as Diesel engines burning hydrocarbonoil fuels.

Fuel ignition in a compression ignition engine never occurssimultaneously with the first appearance of the injected fuel in thecombustion i chamber, but at some time interval thereafter.

This time interval between the initial appearance of the injected fuelin the combustion chamber and its initial spontaneous ignition is termedthe ignition delay or ignition lag, and its dural tion is a measure ofthe ignition qualities of the fuel oil. Different fuels manifestdiflerent qualities in this respect.

The ignition delay has been conveniently expressed by the term delaynumber which is the number of degrees that the crankshaft rotates in theinterval between the beginning of fuel injection and the instant of fuelignition.

Until recently, the rotational speeds of compression ignition engineswere relatively low as compared with the actual ignition delay of theinjected fuels, hence the ignition lag did not materially affect engineperformance even* with fuels having poor ignition characteristics.However, in the recently developed high speed Diesel engines since theactual ignition lag time interval remains substantially constant on anygiven fuel for all engine speed, the same ignition lag time intervaloccupies a greater interval of time relative to the engine cycle, andhence the delay number becomes here proportionally greater. It isapparent, therefore, that the ignition lag characteristics of fuelsbecome of more. and more significance with the increase of Diesel enginespeeds.

unburned fuel accumulates in the combustion chamber during the earlyportion of each injection cycle until spontaneous ignition'flnallyoccurs. A long ignition delay relative to the rota! tional displacementof the crank shaft, or, in other words, fuel ignition characteristicsand relative engine speeds resulting in a high ignition delay numberwill allow, therefore, an excessive "amount of unburned fuel toaccumulate during 5 injection, so that when ignition finally occurs thepressure rise in the combustion chamber due to the sudden combustion ofthe accumulated fuel willreach undesirable or even unsafe limits, and,additionally, the pressure rise will be of such suddenness as to producewhat is known as Diesel As a, result of ignition delay or ignition lag,

knock; This Diesel knock may be even more detrimental to good operationin a Diesel engine than is detonation in a gasoline engine. Fuels whichhave poor ignition qualities are, therefore, the most common cause ofknocking or rough-running 5' high speed compression ignition engines. Itmay also be said that nearly all difficulties that apparently resultfrom improper fuel combustion, such as knocking, rough running, loss ofpower, smoky exhaust and difficulty in cold starting, are 10 primarilycaused by poor ignition resulting from fuel having poor ignitionqualities or high delay numbers. I

Objects of this invention are, therefore, to re- .duce the objectionableignition lag of compression is ignition engine fuels, particularly thosehaving poor ignition qualities.

A further object of this invention is to reduce the delay number offuels, particularly fuels employed in high speed compression ignitioninternal 2o combustion engines.

The objects of this invention are attained in general by employing ozoneas an ignition accelerator.

It has been found that the addition of low con-- 5 centrations of ozoneto the combustion air in to. whichit has been previously added. Ozonemay also be supplied to the combustion zone through an auxiliary valvein the cylinder head '40 either during the air intake portion of thecycle or just prior to or during injection of the fuel. The ozone mayalso be dissolved in the Diesel fuel .01! prior to the injection andthus be carried. into the combustion chamber upon injection in 45solution with the oil.

The ozone may be generated by any of the well known methods. Forexample, ozone can be generated by subjecting a stream of air or oxygento a silent electric discharge or corona 5o discharge between electrodescharged to a high potential differences or the air or oxygen may besubjected to the action of ultra violet light resulting in the formationof ozone. Ozone may also be generated chemically. The chemical reactionbetween nitric acid (HNOs) and ammonium persulfate (NH4)2S2Oa in anatmosphere the oxygen and ozone thus chemically produced fed to theDiesel engine cylinderinthe manner hereinabove described or the wholegaseous mixture including the carbon dioxide as a carrier, may beconveyed to the engine.

Fuels employed for compression ignition internal combustion engines suchas Diesel engine fuels are generally hydrocarbons derived from petroleumand may cover a wide range of gravities and viscosities varying fromlight hydrocarbons in the gasoline range down to petroleum residues orwaxes. Diesel engine fuels which are commonly used, however, range inviscosity from 35 to 125 Saybolt seconds at-100 F. and in gravity from22 to 35 A. P. I. In general, the ignition qualities of thesehydrocarbon fractions appear to vary as a function of theirparafiinicity, those fractions which are most highly parafiinic havingthe lowest delay number, and those fractions which are most highlyaromatic having the highest delay number. p

The employment of ozone as an ignition accelerator is, thus,particularly advantageous with the-hydrocarbon fuel oils which are leastparafllnic in nature.

Ozone is therefore particularly effective in reducing the delay numberof hydrocarbon fuels which contain appreciable quantities of crackedmaterial.

Other types of fuels with which ozone may also be employed as an"accelerator are alcohols, vegetable oils such as palm, cottonseed,corn, and soy bean oils, and animal oils such as sperm-and lard oils. a

The ozone may be used in 'quantities of the order of a thousandth of onepercentup to much larger quantities of the order of several hundredthsof one per centfby volume of the intake air, depending upon thedegree ofignition lag .control desired and the character of the fuel bustionzone, or through the compressed fuelinjection air, or two or more ofthese combined.

The invention also. includes a compression ignition ermine fuel productsuch as Diesel engine fuel comprising a mixture or solution of ozone inoil.

The drawing, which illustrates a preferred embodiment of the apparatusof the invention, shows a cross-sectional elevation of a conventionalcompression ignition internal combustion engine of the Diesel type withits associated valve mechanism, fuel injection nozzle and air intakemanifolding'. The air intake manifolding departs from theconventionalarrangement in comprising an air inlet Il'and an ozonizerboth coupled to a common manifold pipe I2 which leads to the intake portI3 of the power; cylinder I4.

.The ozonizer comprises a cylindrical tubing section II containing acoaxial rod electrode 20 which is supported andelectrically insulatedfrom the tubing II at the flanged head 2|. An

' alternating current generator G, a high tension transformer T andsuitable interconnecting conductors 23 and 24 are provided formaintaining a high electric potential between the electrode 20 and theinside surface of the ozonizer cylinder II. The generator G'andtransformer T are preferably adapted to supply a high frequencyalternating electric potential to. the ozonizer. Butterfly valves 25 and26 are provided as suitable pivots in the branches of the manifoldingfor controlling the proportion of air drawn through intake I0 andthrough the ozonizer II exhaust valve I8 is therefore closed and intakevalve I9 open to allow passage of air from the manifold I2 into thecylinder IE.

As the crank I5 continues in rotation as shown by arrow 30 the air-ozonemixture is drawn into the cylinder and upon completion of the intakeportion of the cycle, valve I9 closes and the airozone mixture iscompressed until, at the top of the stroke of the piston II, thetemperature of the mixture ,in the combustion chamber is sufficientlyhighto spontaneously ignite the oil fuel which is then introducedthrough line 32 and into the cylinder through the injector 3|. TheDiesel cycle is thus initiated and repeated in rapid succession witheach revolution of the engine.

In an optionable method of operation of this invention the ozone insteadof being mixed with the intake air may be introduced into the cylindertogether with the fuel and when this operation is desired the ozone maybe introduced into the combustion chamber through the fuel injector 3 I,alongwith injection air. In this case the ozone from a suitablegenerator is mixed with the injection air in line 33 at suitablepressure by means of pipe 34 and the quantity regulated by v valve 35.

. the invention.

I claim: I

1. In a compression ignition internal combustion engine cycle the stepscomprising compressing ozone-containing gas and corningling fuel to beburned with said compressed gas.

2. In a compression ignition internal combustion engine cycle, the stepscomprising compressing ozone-containing gas to the ignition temperatureof the fuel to be burned and injecting the fuel into the thus compressedgas.

I 3. In a compression ignition internal combustion engine cycle thesteps comprising injecting ozone-containing gas into a combustionchamber, compressing the mixture to the ignition temperature of the fuelto be burned and subsequently injecting the said fuel into the saidcompressed mixture.

4. In a compression ignition internal combustion engine cycle the stepscomprising compressing gas containing oxygen in a combustion chamber tothe ignition temperature of the fuel to be burned and subsequentlyinjecting ozone-containing gas and the said fuel into the combustionchamber.

5. In a compression ignition internal combustion engine cycle the stepscomprising compressing gas containing oxygen in a combustion chamber tothe ignition temperature of the fuel to be burned, intermingling ozoneand a quantity of injection air, and injecting fuel together with the isaid injection air into the said compressed gas in the combustionchamber.

6. In a compression ignition internal combustion cycle where the fuel isa normally liquid hydrocarbon fraction, heavier than gasoline, the stepscomprising compressing a mixture of ozone and air in the combustionchamber to the ignition temperature of said hydrocarbon fuel andsubsequently injecting a quantity of said fuel into said compressedozone-air mixture in said combustion chamber, whereby combustion takesplace and power is developed.

7. A compression ignition internal combustion engine apparatuscomprising in combination a combustion chamber, an ozone generator,means to introduce ozone from said ozone generator into said combustionchamber, means to compress gases in said combustion chamber to theignition temperature of fuel to be burned and means to comminglecombustible fuel with said ozone in said chamber.

8. A compression ignition internal combustion engine apparatuscomprising in combination a combustion chamber, means to commingle air,ozone and a combustible fuel in said combustion chamber and means tocompress gases in said combustion chamber to the ignition temperature offuel to be burned.

9. Apparatus according to claim 8 in which the means to commingle air,ozone and combustible fuel comprises an air injection fuel nozzle andmeans to introduce ozone into the injection air.

CHARLES CHILTON MOORE, JR.

